Telephone receiver



Dec. .10, 1929. A. H. INGLIS ET AL 1,738,653

' TELEPHONE RECEIVER Filed NOV. 24, 1925 INVENTQRS a B 1?. Glee/mike,

5 4 if? 9; ATTORNEY Patented Dec. 10, 1929 UNITED STATES PATENT OFFICE ALFRED H. 'nmLzs, E ORANGE, AND AYMOND GUEETHER, 0E PATEBSON, NEw

JERSEY, AssmNoRs-To AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A

CORPORATION OF NEW YORK v TELEPHONE RECEIVER Application filed November 24, 1925. Serial No. 71,251.

This invention relates totelephone receivers and consists in a novel construct1on and mounting of the rec'elver diaphragm.

As is well known in the art, the diaphragm of the ordinary telephone receiver is a thin iron disc clamped tightly between the brass receiver case and the hard rubber cap and lying 0 posite the pole pieces of the magnetic unit. ith this construction and arrangement of the diaphragm, there are certain undesirable eifects of temperature changes and also the likelihood of acoustic shock. F urthermore, there are undesirable resonance effects, due to the sharply defined natural pcriod of vibration of the diaphragm.

Applicants invention has as its principal objects the elimination of the effects of 'temperature changes, the elimination, or at least the minimization, of the resonance effects, and the elimination of acoustic shock. In addition to the advantages found inthe attainment of these objects, the improved receiver has other advantages which will be disclosed and discussed below. v In order to attain the objects named above applicants provide a floating diaphragm of novel construction and design.

- This diaphragm structure and the arrangement of its mounting will be more clearly understood when the following detailed description is read with reference to the acc' mpanying drawing. Figure 1 of the drawing shows in cross-section the referred form of applicants receiver, and Fig. 2 is an enlarged 5- cross-sectional View of the diaphragm and the mounting therefor. It is to be understood that the form and proportions of the diaphragm and the spacing are greatly exaggerated, for purpose of clear descri tion. Like numerals of reference in the two gures of the drawing designate corresponding parts ofthe device. 7

With reference to the details of the drawing, the receiver case 1, the receiver cap 2, and the electromagnets Sand 4, with their pole ieces 5 and 6, respectively, are parts found in the ordinary receiver. v

The diaphragm structure comprises two members, the diaphragm proper 7 and the magnetic diaphragm or armature 8. The

member 7 is constructed from a thin piece of suitable metal of very light weight, such as duralumin, non-magnetic andhavin a relatively low specific-resistance. It is shown in the form of a shallow cone with a flat top, but any. form givin rigidity is suit-able. The member 8 is fi'xe to the under side of the flat portion of the diaphragm 7 and consists of a I small, thin disc of magnetic material of high permeability, such as permalloy. This member 8 lies oposite and close to the pole pieces 5 and 6 and acts as an armature. The diaphragm 7, together with the magnetic diaphragm 8 attached thereto, instead of be ing tightly clamped between the receiver case and cap, is loosely supported between piles of thin washers 9 and 10. These washers should be of thin material such that the piles of washers will include suflicient air between layers to provide air damping of the movin system. Condenser paper is suitable, an aluminum foil is also found to be satisfactory. A spun metal ring 11, of brass or an other suitable material and of any suitab e construction, may be used to hold this assembly in a single unit. I

The member 8 must be constructed of a. material which has the characteristics of higher initial permeability than iron and a lower value of magnetization at saturation. Permalloy is the most desirable material known to the applicants, and a suitable variety of permalloy is a composition of nickel and iron, in which the nickel component predominates. In certain cases it may be desirable, for reasons other than those relating directly to this invention, that ingredients other than nickel and iron be added to the composition. The

plified description and discussion of permalloy and its production, reference may be had to the disclosure found in the United States the following ad- I A 1. The diaphra structure, bein of very li htwei htanda ihg air-damped virtue o the p' es of washers between WhlQh' it is mounted, will act, not as a vibrating diaphragm, but as a plunger, and will have a.

very slight or no natural period. The greatly reduced mass of moving parts produces an 7 improved match of acoustic impedance becase, changes of temperature do not distort the diaphragm and alter: the separation between t at structure and the pole' pieces of the magnetic device, but, on the contrary,

- receiver having a there is a practically constant separation overuently a wide range of temperature. 00 a much smaller initial se aration may vided, with the result 0 greater eflicieucy.

3. The use of the small magnetic diaphragm with a sharp maggetic saturation point, combined with and sudden increase in volume, owever,

flux will. cut the duralumin diap seteddy' currents, which will eavily dam t e moving system and thus reduce the resu tant displacement to a point at which it will not be 0 jectionable.

vIt is thus seen that applicants provide a ter motor efliciency than is the case wit the ordinary receiver, since a much smaller separation can be maintained betweenthe pole pieces and the dia-' phragm structure without danger of freezing. Again, the improved receiver will be more leasant'to use than theordinary receiver ause of. the reduction of the resonance efiects and the elimination of acoustic shock. Furthermore, applicants" receiver can be ad- -vantageously' used on a hand set, since the response is not so marked as it is in the ordinary receiver, and consequently of howlin is materially reduced.

While t e invention has been disclosed in one s ecific embodiment which is deemed desirab c, it is to be understood that it is capable vmember fixedly mounted being ed to a diaphragm of low' specific resistance, as disclosed, will eliminate, reduce, acoustic shock."

.saturate the armature. In such a case the said member having the danger 'ablhty than iron and lower magnetization atmember fixedly mounted on said diaphragm in proximity to saidmagnetic dev ce, said member ha higher-.initial'permeability than iron and ower value of magnetization at saturation.

2. A telephone receiver including a netic device, a floating diaphragm, ai iii a memberfixedly mounted on said diaphragm 1n proximity to said magnetic device, said memberbeilgeofa magnetic alloy co chiefly of ni l and iron and having a higher initial netization at saturation.

3. A telephone receiver including a magnetic device, a floating diaphr and a on said diaphragm in proximity .to said magnet device and ponenet predominates, said member having higher initial permeability than iron and lower magnetization at saturation.

4. A telephone receiver including a magnetic device, a floa diaphragm, and a permalloy member fix ymounted on said g p mp yt i magnetic evice.

5. A telephone receiver a m netic device, a floating dia hragm of ndl imagnetic material havmg tivel low specific resistance, and a member fix y mounted on said diaphragm in roximity to said 111 etic device said mem having her permeability than iron and loweiirilue of magnetization at saturation.

6 A telephone receiver including a mag-. net c device, a floating dia hragm of nonmagnetic material having low spev tivel cific resistance, and a member fixediy mounted on said'diaphra V in proximity to said magnetic device, sai' member being of a magnetic alloy consistinfichiefly of nickel and iron and aving hig er initial permeability tlon.

I 7. A telephone receiver including a magnetic device, a floating dia hragm of nonmagnetic material having re ativel low specific reslstance, and a member fixediy mounted on said diaphragm in proximity tov said ma sistmg chiefly of nickel and iron and in of an alloy consisting chiefly of nickel and non and in which the nickel com etic device and being ofan alloy conpermeability than iron and lower mag-.

than iron and lower magnetization at satu'rawhich the nickel comgogient predominates,

her initial permesaturation. r 8. A telephone-receiver including a magnetic device, a floating dia hragm of nonspecific resistance, andv a, member fixedly mounted on said diaphragm in proximity to said magnetic device, said member having higher initial permeability than iron and.- lower value of magnetization at saturation.

In testimony whereof, We have signed our names to this specification this 23rd day of November 1925. v

ALFRED H. INGLIS.

RAYMOND GUENTHER. I 

